代码：
#include<iostream>
#include<map>
#include<vector>
using namespace std;
int main(){
int m,n,s;
cin>>m>>n>>s;
map<string,bool> mp;
vector<string> v(m+1);
for(int i=1;i<=m;i++) cin>>v[i];
if(s>m) cout<<"Keep going..."<<endl;
else{
for(int temp=s;temp<=m;temp+=n){
while(temp<=m&&mp[v[temp]]) temp++;
if(temp>m) break;
cout<<v[temp]<<endl;
mp[v[temp]]=true;
}
}
return 0;
}